Abstract
In this work, we use finite-difference time domain method to simulate the spectral response and near-field intensity distribution of bowtie antenna and found that under the excitation of and, the enhanced factor of antenna with the height of is larger than the antenna with the height of . When studying the near-field intensity distribution, the electric energy will concentrate on the apex of bowtie antenna in the metal-air side and its magnitude will decay with increasing observation distance. The decay rate is proportional to the reciprocal of six power of distance. Considering the polarization of incident light, when polarization is parallel to antenna axis, the enhancement will be larger than the polarization perpendicular to antenna axis. In the aspect of sample process, we utilize the electron beam lithography to design and fabricate nano-antenna array on quartz substrate under the condition of and . Then, in the aspect of measurement, we use home-made collection mode near-field scanning optical microscope with attenuated total internal reflection set-up to obtain the real near-field intensity distribution of bowtie antenna array by shear force feedback. Finally, we compare the experimental results with the simulation data, and have a very close conclusion.